SEABROOK — Seabrook Station nuclear power plant officials say the concrete degradation issue at the heart of a recent quarterly inspection safety finding isn't a new issue.

Two "green" findings, or findings of "very low safety significance," and one non-cited violation were discovered during a June 30 Nuclear Regulatory Commission inspection.

One of the "green" findings relates to degradation in the plant's concrete residual heat removal vaults. The inspectors claim NextEra Energy, the plant's owners, didn't do enough to formally evaluate this area during the course of the plant's monitoring program.

Al Griffith, a spokesman for the plant, said this degradation has been part of the plant's maintenance plan since 2006, although he said the plant will now perform a "more formalized evaluation" of the vaults as a result of the inspection.

He also said the plant will continue to "make sure" the structures are "fully capable of performing (their) design function today and long into the future."

In their June 30 report, NRC inspectors deemed the issue a "performance deficiency" and said it was considered "more than minor because it affected... the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences."

Despite this, NRC inspectors said it "did not represent an actual loss of function."

The plant has drawn criticism from the public in recent years due to findings that an alkali-silica reaction within the plant's concrete is causing cracking and degradation.

Those criticisms have come as NextEra seeks a 20-year extension of its license from 2030 to 2050. The NRC has said a decision on that application won't be made until NextEra completes a number of steps to address the degradation.

NRC Public Affairs Officer Neil Sheehan said there is "no evidence at this point" that the cracking found in the residual heat removal vaults is the "result" of ASR.